Merge pull request #635 from Classic298/patch-3

small changes to add the necessity to configure `OPENID_PROVIDER_URL` so logout works fine

Author: tjbck

docs/features/sso/index.mdx

@@ -14,16 +14,31 @@ Open WebUI supports several forms of federated authentication:
     1. OIDC
 1. Trusted Header
 
+:::info
+
+For more information about all environment variables, check out the [environment variable docs page](https://docs.openwebui.com/getting-started/env-configuration/).
+It is highly recommended to check the environment variable page, to get more details about how to set the variable and what values are expected.
+
+:::
+
+:::danger
+
+Right now, you can only configure one OAUTH provider at a time.
+You cannot have Microsoft **and** Google as providers simultaneously.
+
+:::
+
 ## OAuth
 
-There are several global configuration options for OAuth:
+There are several global configuration options for OAuth in general:
 
 1. `ENABLE_OAUTH_SIGNUP` - if `true`, allows accounts to be created when logging in with OAuth. Distinct from `ENABLE_SIGNUP`.
 1. `OAUTH_MERGE_ACCOUNTS_BY_EMAIL` - allows logging into an account that matches the email address provided by the OAuth provider.
     - This is considered insecure as not all OAuth providers verify email addresses, and may allow accounts to be hijacked.
 1. `OAUTH_UPDATE_PICTURE_ON_LOGIN` - if `true`, users will have OAuth-provided profile pictures updated on login.
     - If the OAuth picture claim is disabled by setting `OAUTH_PICTURE_CLAIM` to the empty string, this configuration will be ignored.
 1. `OAUTH_PICTURE_CLAIM` - can be used to customize or disable profile picture storage. The default, `picture`, will work for most providers; if set to the empty string, all users will receive the default person profile picture.
+1. `WEBUI_AUTH_SIGNOUT_REDIRECT_URI` - can be set to optionally forward the user to a specific URI after logging out.
 
 ### Google
 
@@ -34,6 +49,7 @@ The following environment variables are required:
 
 1. `GOOGLE_CLIENT_ID` - Google OAuth client ID
 1. `GOOGLE_CLIENT_SECRET` - Google OAuth client secret
+1. `OPENID_PROVIDER_URL` - Must be set for logout to work properly.
 
 ### Microsoft
 
@@ -45,9 +61,10 @@ Support for Microsoft OAuth is currently limited to a single tenant, that is a s
 The following environment variables are required:
 
 1. `MICROSOFT_CLIENT_ID` - Microsoft OAuth client ID
-2. `MICROSOFT_CLIENT_SECRET` - Microsoft OAuth client secret
-3. `MICROSOFT_CLIENT_TENANT_ID` - Microsoft tenant ID - use `9188040d-6c67-4c5b-b112-36a304b66dad` for personal accounts
-4. `MICROSOFT_REDIRECT_URI` - The redirect URI configured in your Microsoft OAuth application. This must be set to `<open-webui>/oauth/microsoft/callback`.
+1. `MICROSOFT_CLIENT_SECRET` - Microsoft OAuth client secret
+1. `MICROSOFT_CLIENT_TENANT_ID` - Microsoft tenant ID - use `9188040d-6c67-4c5b-b112-36a304b66dad` for personal accounts
+1. `MICROSOFT_REDIRECT_URI` - The redirect URI configured in your Microsoft OAuth application. This must be set to `<open-webui>/oauth/microsoft/callback`.
+1. `OPENID_PROVIDER_URL` - Must be set for logout to work properly.
 
 ### Github
 
@@ -58,6 +75,7 @@ The following environment variables are required:
 
 1. `GITHUB_CLIENT_ID` - Github OAuth App Client ID
 1. `GITHUB_CLIENT_SECRET` - Github OAuth App Client Secret
+1. `OPENID_PROVIDER_URL` - Must be set for logout to work properly.
 
 ### OIDC